Scholarly Publications (Department of Biological Sciences)https://hdl.handle.net/11668/54392018-11-19T22:43:16Z2018-11-19T22:43:16ZAsymmetrical gene flow in a hybrid zone of Hawaiian Schiedea (Caryophyllaceae) species with contrasting mating systems.Wallace, Lisa E.Culley, Theresa M.Weller, Stephen G.Sakai, Ann K.Kuenzi, AshleyRoy, TilottamaWagner, Warren L.Nepokroeff, Mollyhttps://hdl.handle.net/11668/25032018-04-04T15:46:23Z0009-01-01T00:00:00ZAsymmetrical gene flow in a hybrid zone of Hawaiian Schiedea (Caryophyllaceae) species with contrasting mating systems.
Wallace, Lisa E.; Culley, Theresa M.; Weller, Stephen G.; Sakai, Ann K.; Kuenzi, Ashley; Roy, Tilottama; Wagner, Warren L.; Nepokroeff, Molly
Asymmetrical gene flow, which has frequently been documented in naturally occurring hybrid zones, can result from various genetic and demographic factors. Understanding these factors is important for determining the ecological conditions that permitted hybridization and the evolutionary potential inherent in hybrids. Here, we characterized morphological, nuclear, and chloroplast variation in a putative hybrid zone between Schiedea menziesii and S. salicaria, endemic Hawaiian species with contrasting breeding systems. Schiedea menziesii is hermaphroditic with moderate selfing; S. salicaria is gynodioecious and wind-pollinated, with partially selfing hermaphrodites and largely outcrossed females. We tested three hypotheses: 1) putative hybrids were derived from natural crosses between S. menziesii and S. salicaria, 2) gene flow via pollen is unidirectional from S. salicaria to S. menziesii and 3) in the hybrid zone, traits associated with wind pollination would be favored as a result of pollen-swamping by S. salicaria. Schiedea menziesii and S. salicaria have distinct morphologies and chloroplast genomes but are less differentiated at the nuclear loci. Hybrids are most similar to S. menziesii at chloroplast loci, exhibit nuclear allele frequencies in common with both parental species, and resemble S. salicaria in pollen production and pollen size, traits important to wind pollination. Additionally, unlike S. menziesii, the hybrid zone contains many females, suggesting that the nuclear gene responsible for male sterility in S. salicaria has been transferred to hybrid plants. Continued selection of nuclear genes in the hybrid zone may result in a population that resembles S. salicaria, but retains chloroplast lineage(s) of S. menziesii.
0009-01-01T00:00:00ZQuantitative field testing Rotylenchulus reniformis DNA from metagenomic samples isolated directly from soil.Showmaker, KurtLawrence, Gary W.Lu, ShienBalbalian, ClarissaKlink, Vincent P.https://hdl.handle.net/11668/24962018-04-04T15:46:23Z0012-01-01T00:00:00ZQuantitative field testing Rotylenchulus reniformis DNA from metagenomic samples isolated directly from soil.
Showmaker, Kurt; Lawrence, Gary W.; Lu, Shien; Balbalian, Clarissa; Klink, Vincent P.
A quantitative PCR procedure targeting the ?-tubulin gene determined the number of Rotylenchulus reniformis Linford & Oliveira 1940 in metagenomic DNA samples isolated from soil. Of note, this outcome was in the presence of other soil-dwelling plant parasitic nematodes including its sister genus Helicotylenchus Steiner, 1945. The methodology provides a framework for molecular diagnostics of nematodes from metagenomic DNA isolated directly from soil.
0012-01-01T00:00:00ZInferred vs realized patterns of gene flow: an analysis of population structure in the Andros Island Rock Iguana.Colosimo, GiulianoKnapp, Charles R.Wallace, Lisa E.Welch, Mark E.https://hdl.handle.net/11668/24982018-04-04T15:46:23Z0009-01-01T00:00:00ZInferred vs realized patterns of gene flow: an analysis of population structure in the Andros Island Rock Iguana.
Colosimo, Giuliano; Knapp, Charles R.; Wallace, Lisa E.; Welch, Mark E.
Ecological data, the primary source of information on patterns and rates of migration, can be integrated with genetic data to more accurately describe the realized connectivity between geographically isolated demes. In this paper we implement this approach and discuss its implications for managing populations of the endangered Andros Island Rock Iguana, Cyclura cychlura cychlura. This iguana is endemic to Andros, a highly fragmented landmass of large islands and smaller cays. Field observations suggest that geographically isolated demes were panmictic due to high, inferred rates of gene flow. We expand on these observations using 16 polymorphic microsatellites to investigate the genetic structure and rates of gene flow from 188 Andros Iguanas collected across 23 island sites. Bayesian clustering of specimens assigned individuals to three distinct genotypic clusters. An analysis of molecular variance (AMOVA) indicates that allele frequency differences are responsible for a significant portion of the genetic variance across the three defined clusters (Fst = 0.117, p<0.01). These clusters are associated with larger islands and satellite cays isolated by broad water channels with strong currents. These findings imply that broad water channels present greater obstacles to gene flow than was inferred from field observation alone. Additionally, rates of gene flow were indirectly estimated using BAYESASS 3.0. The proportion of individuals originating from within each identified cluster varied from 94.5 to 98.7%, providing further support for local isolation. Our assessment reveals a major disparity between inferred and realized gene flow. We discuss our results in a conservation perspective for species inhabiting highly fragmented landscapes.
0009-01-01T00:00:00ZMulti-allelic major effect genes interact with minor effect QTLs to control adaptive color pattern variation in Heliconius erato.Papa, RiccardoKapan, Durrell D.Counterman, Brian A.Maldonado, KarlaLindstrom, Daniel P.Reed, Robert D.Nijhout, H. FrederikHrbek, TomasMcMillan, W. Owenhttps://hdl.handle.net/11668/24912018-04-04T15:46:22Z0003-01-01T00:00:00ZMulti-allelic major effect genes interact with minor effect QTLs to control adaptive color pattern variation in Heliconius erato.
Papa, Riccardo; Kapan, Durrell D.; Counterman, Brian A.; Maldonado, Karla; Lindstrom, Daniel P.; Reed, Robert D.; Nijhout, H. Frederik; Hrbek, Tomas; McMillan, W. Owen
Recent studies indicate that relatively few genomic regions are repeatedly involved in the evolution of Heliconius butterfly wing patterns. Although this work demonstrates a number of cases where homologous loci underlie both convergent and divergent wing pattern change among different Heliconius species, it is still unclear exactly how many loci underlie pattern variation across the genus. To address this question for Heliconius erato, we created fifteen independent crosses utilizing the four most distinct color pattern races and analyzed color pattern segregation across a total of 1271 F2 and backcross offspring. Additionally, we used the most variable brood, an F2 cross between H. himera and the east Ecuadorian H. erato notabilis, to perform a quantitative genetic analysis of color pattern variation and produce a detailed map of the loci likely involved in the H. erato color pattern radiation. Using AFLP and gene based markers, we show that fewer major genes than previously envisioned control the color pattern variation in H. erato. We describe for the first time the genetic architecture of H. erato wing color pattern by assessing quantitative variation in addition to traditional linkage mapping. In particular, our data suggest three genomic intervals modulate the bulk of the observed variation in color. Furthermore, we also identify several modifier loci of moderate effect size that contribute to the quantitative wing pattern variation. Our results are consistent with the two-step model for the evolution of mimetic wing patterns in Heliconius and support a growing body of empirical data demonstrating the importance of major effect loci in adaptive change.
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